To reproduce:

1. Open the project, attached by tester (compileAtRuntime.zip)
2. Open "test" scene
3. Enter Play mode
4. Observe the console (StateMachineBehaviour is FOUND)
5. Edit CapsuleMind script without exiting the Play mode
6. Return to Unity
7. Observe the console (StateMachineBehaviour is NOT FOUND)

Expected: StateMachineBehaviour is found after recompiling the code in Play mode
Actual: script recompilation at runtime causes Animator.GetBehaviour to not find the specified StateMachineBehaviour

Reproduced in 5.6.0b11, 5.6.0f3, 2017.1.0b6, 2017.2.0a1
Did not reproduce in 5.5.3p2, 5.6.0a1, 5.6.0b6, 5.6.0b9, 5.6.0b10
Regression introduced in 5.6.0b11